JPS622526B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field The present invention is capable of monitoring diseases where blood circulation failure is expected and estimating blood flow in the palms, toes, etc. by measuring heat dissipation from the skin surface. The present invention relates to a heat flow density measuring device on the surface of a living body, which is used to measure the heat flow density on the surface of a living body.

(2) Background technology When a person falls into a critical condition due to a disease that involves poor blood circulation, such as heart disease, the first sign of this is that the amount of blood flowing to the hands and feet, which are far from the heart, decreases.
The hands and feet become cold before the rest of the body.
Therefore, by measuring the heat flow from the skin surface of the affected area or hands and feet over time, it is possible to monitor the state of blood flow in patients who are expected to suffer from poor blood circulation, especially in the early stages of becoming seriously ill. can be prevented from becoming a serious condition by taking appropriate measures before the condition becomes serious. Therefore, it is desired to provide a heat flow density measuring device on the surface of a living body that can measure heat dissipation from the skin surface. In addition, a heat flow density measuring device on the surface of a living body is a necessary measuring device along with a deep temperature measuring device to estimate the blood flow rate in each part of the living body. However, in an equilibrium state, the local temperature of an organism is determined by heat inflow and outflow through blood flow, heat dissipation from the skin, and tissue heat production; heat generated within the body is determined by conduction and blood flow. It is carried to the skin and dissipated outside the body through conduction, convection, radiation, and transpiration from the skin surface.
It is clear that skin blood flow plays an important role in regulating body temperature, and therefore, in order to estimate blood flow in a living body, it is necessary to measure the body's deep temperature as well as the heat flow density dissipated from the skin surface. This is because.

Regarding the possibility of estimating tissue blood flow in the human body using a core thermometer and a heat flow meter, the results of joint research between the present inventors and Messrs. Akira Kamiya, Masatoshi Tanaka, and Kenji Kawakami are as follows: A paper entitled "Estimation of Blood Flow Using Temperature" was published in a medical research journal; Medical Equipment Research Report Vol. 13, P27-P37 (published in 1979).

However, the conventional heat flow density measuring device on the surface of a living body is as shown in FIG. A thermocouple 1b is differentially wired inside the thermal resistor so as to generate a voltage, and its front and back surfaces are covered with coating materials 1c, 1.
It consisted of a heat flow sensor 1 (hereinafter simply referred to as a thermopile) consisting of a heat flow sensor 1 (hereinafter referred to simply as a thermopile), and a calculation display 2 that calculated and displayed a predetermined amount of heat flow from the voltage generated in the thermopile 1. The device for measuring heat flow density on the surface of a living body configured as described above has the disadvantage that because the device is placed in close contact with the skin surface, heat is trapped and the heat flow dissipated from the skin surface is deflected, resulting in a lower heat flow density than the true value. have.

The theory behind why the above-mentioned drawbacks exist is explained below. Figure 2 and 2 are concepts showing the state of heat transfer (conduction) from inside the living body to the living body surface A and the state of heat dissipation from the living body surface A, respectively. FIG. 3 is a conceptual diagram showing the temperature gradient of heat conduction within a living body and radiation from the surface of the living body. Figures 2 and 3 show the case where the biological surface is not covered with anything, the heat flow density is the true value to be measured, the heat flow is uniform in the vertical direction of the biological surface, and the temperature gradient is the deep temperature of the biological body. t ₁ is approximately 36℃ to 38℃, temperature t ₂ of biological surface A is approximately 34℃
, and when the temperature is slightly away from the biological surface A, the temperature rapidly drops to the atmospheric temperature t _a . Figure 2 shows a state in which the thermal resistor B is applied to the surface A of the living body, and the thermal resistor B does not heat up. Thermal resistor B is in a warm, equilibrium state. Now, biological surface A
At the stage where the thermal resistor B applied to the _t The heat conducted to the thermal resistor B is absorbed due to the temperature increase, and the heat flow density flowing through the thermal resistor B becomes larger than the true value heat flow density shown in FIG. Then, as the thermal resistor B gradually warms up, the concentration of heat flow becomes weaker, and the heat flow density approaches the true value. When the temperature of the part of the biological surface A where thermal resistor B is applied recovers to the temperature before applying thermal resistor B, at that point the heat flow density flowing through thermal resistor B is equal to that of the thermal resistor. It is equal to the true value of the heat flow density due to convection and radiation on the biological surface A that is not covered by B, and the heat dissipation of the biological body is as shown in Figure 2, both in areas where thermal resistor B is applied and in areas where it is not applied. This results in a similar even heat flow. Furthermore, as shown in Figure 3, the temperature _t2 of the biological surface A rises above the temperature when the heat resistor B is not applied, that is, the true skin temperature, and the deep body temperature rises. As the temperature rises to a point t ₂ ' close to , as shown in FIG. 2, a considerable amount of the heat flow approaches the thermal resistor B and concentrates around it where the temperature difference is large. Therefore, the heat flow density of the thermal resistor B becomes lower than the true value. For the reasons mentioned above, the conventional heat flow density measuring device shown in FIG. 1 has the drawback that it cannot measure the true value of heat flow density.

However, as a result of intensive studies by the present inventors in order to eliminate the above-mentioned drawbacks, as shown in FIG. 3, by applying a cooling panel C having a cooling function to the outer surface of the thermal resistor B, If _the external surface temperature t _{3 of} the thermal resistor B shown in _FIG . It has been recognized that, if possible, the heat flow flowing through the thermal resistor B will have a true value without being deflected as shown in FIG.

Therefore, this invention can maintain the temperature of the biological surface at the skin temperature even when a thermopile, which is a heat resistor, is applied to the biological surface, and thereby maintains the true value of the heat flow density without causing a deflection of the heat flow. It can be measured over time and can also track changes in heat flow density due to insufficient blood flow, which is a sign of deterioration in the patient's condition, making it possible to detect sudden changes in the patient's condition in diseases where blood circulation failure is expected. The purpose of the present invention is to provide a heat flow density measuring device on the surface of a living body, which is more reliable and reliable in detecting signs of heat flow, and more accurate in estimating blood flow in the palms, toes, etc.

(3) Disclosure of the invention The apparatus for measuring heat flow density on the surface of a living body according to the present invention comprises two
It consists of two sensor sections and a control display section. One sensor section consists of a thermopile with a cooling panel made of an electronic cooling element superimposed on it, and a control thermistor attached to the surface of the thermopile. It consists of a thermistor for skin temperature detection that is separately applied to the surface, and the control display section includes a first amplifier that amplifies the output signal of the thermopile, and a recording output section that calculates and records the output signal of this amplifier into a heat flow density. , second and third amplifiers that amplify the output signals of the two thermistors, respectively, a differential amplifier that inputs the output signals of these second and third amplifiers and outputs a difference signal, and the cooling panel. Thermoelectric cooling element control that allows current to flow in a predetermined direction through the thermoelectric cooling element so that the surface joined to the thermopile is on the heat absorption side, and the magnitude of the current can be feedback-controlled by inputting the output signal of the differential amplifier. It is characterized by consisting of two parts.

Therefore, according to the heat flow density measuring device on the surface of a living body of the present invention, even when the thermopile is applied to the surface of the living body, the heat flow density flowing through the thermopile can be substantially changed by cooling control of the electronic cooling element. Moreover, such changes can be made by controlling the electronic cooling element using the difference signal between the skin temperature detection thermistor and the control thermistor to maintain the skin temperature of the area to which the thermopile is applied to the skin temperature of the nearby area to which the thermopile is not applied. When the patient's condition deteriorates and the blood flow is insufficient, reducing the heat flow radiated from the skin, the skin temperature in the area to which the thermopile is not applied will drop faster than the skin temperature in the area to which the thermopile is applied. The thermopile surface temperature can be controlled so that the skin temperature of the area to which the thermopile is applied becomes the true skin temperature after the condition has deteriorated, by detecting the difference signal with two temperature sensing elements and controlling the electronic cooling element. Therefore, in any case, the heat flow density flowing through the thermopile is not deflected, and the true value of the heat flow density can be recorded at the recording output section.

(4) Best Mode for Carrying Out the Invention (4-1) Configuration The apparatus for measuring heat flow density on the surface of a living body according to the present invention has two sensor sections L and M as shown in the block circuit diagram of FIG. and a control display section N. As shown in FIG. 5, the first sensor section L includes a thermopile 1 similar to the conventional one shown in FIG. A control thermistor 4 for detecting the thermopile surface temperature is placed approximately in the center of the surface of the thermopile 1 by overlapping the cooling panels 3 arranged in a thin plate shape, and further overlapping the plate part 5a of the heat dissipation fin 5 on the surface of the cooling panel 3. It consists of an attached. Another sensor part M
The thermistor 6 for detecting skin temperature is supported on a support 7, and the support 7 is formed in a ring shape so that it can be applied stably to the surface of the living body separately from the sensor part L. It is supported so that it faces the center of the shape. The control display section N also includes a first amplifier 9 that amplifies the output signal 8 of the thermopile 1, a recording output section 10 that calculates and records the output signal of the amplifier 9 into a heat flow density, and an amplifier 9.
A digital display meter 11 which calculates the output signal of 3 amplifier 1
A differential amplifier 16 inputs the output signals of 4 and 15 and outputs a difference signal, and the electronic cooling element 3a is oriented in a predetermined direction so that the surface portion 3b of the cooling panel 3 connected to the thermopile is on the heat absorption side. current 17
and the magnitude of the current 17 in the differential amplifier 1.
6, and a recording output section 20 which inputs the output signal of the third amplifier 15 and calculates and records the temperature. The digital display meter 11 is connected to a third amplifier 15.
The terminal is switchable so that the output signal can be input, so that the true skin temperature can always be displayed digitally. The differential amplifier 16 is configured to output a positive difference signal 18 if the temperature detected by the thermistor 4 is higher than the temperature detected by the thermistor 6, and output a negative difference signal 18 if it is lower. At this time, the electronic cooling element control section 19 generates a current of 1 in proportion to the positive or negative difference signal 18.
It is assumed that the size of 7 can be changed.

(4-2) Effect Now, as shown in Fig. 6, the surface of the thermopile 1 of the sensor part L is applied to the arm of a patient with poor blood circulation, and the sensor part M is also applied to measure the heat flow density in the skin over time. shall be measured. In this case, when the thermopile 1 is applied to the arm without energizing the electronic cooling element 3a, the true skin temperature t ₂ immediately before application is t ₂ ' because the thermopile 1 is cold, as shown in FIG. The temperature drops to
If the electronic cooling element 3a is not energized and therefore the cooling panel 3 is not cooled, the thermopile 1, which is a thermal resistor, receives heat from the skin and warms up in a short time, and the amount of heat trapped in the body gradually increases. , the skin temperature of the area covered by the thermopile 1 gradually rises from t ₂ ′, passes through t ₂ , and when the heat conduction reaches the heat dissipation fins 5 sufficiently, the temperature reaches a temperature t ₂ ″ close to the deep temperature. Such a temperature change can be recorded on a temperature recorder (not shown) connected to the thermistor 4. On the other hand, the record output unit 20 and digital display meter 11 connected to the thermistor 6 each record the skin temperature. t ₂ is recorded and displayed without any change. Therefore, when you turn on the main switch (not shown) in the control display section N (note: it is turned on at this stage to make the explanation easier to understand, but even if you turn it on from the beginning ), a direct current 17 in a predetermined direction and magnitude controlled by the thermoelectric cooling element control section 19 flows to the thermoelectric cooling element 3a, and the cooling panel 3 made of the thermoelectric cooling element 3a is connected to the thermopile 1.
The heat is actively transferred to the heat generating side and radiated from the heat dissipation fins 5, and the skin temperature of the part of the body covered by the thermopile 1 is lowered from the previous t2 _' '.Therefore, The temperature after falling is
Assume that the temperature is t ₂ or t _{2 〓} close to t ₂ (note that the change from t ₂ ″ to t ₂ or t ₂ 〓 is almost equal to the change in the surface temperature of thermopile 1.)
The surface temperature of thermopile 1 is t ₂ (or t ₂ 〓)
When the thermistor 4 is cooled to a temperature of
After being amplified in step 16, a positive (or negative) difference signal 15 is outputted in differential amplifier 16. The output signal 18 from the differential amplifier 16 is input to the thermoelectric cooling element control section 19 as a feedback signal. This feedback signal 18 becomes a positive signal when the temperature t ₂ detected by the temperature sensing element 4 is higher than the temperature t ₂ detected by the temperature sensing element 6.
A larger current flows through a than before, cooling the thermopile 1 becomes stronger, and the detected temperature t ₂ of the thermosensing element decreases and approaches t ₂ . If the temperature t ₂ 〓 is lower than the temperature t ₂ detected by the temperature sensing element 6, a negative signal will be generated, so a smaller current flows through the electronic cooling element 3a than before, weakening the cooling of the thermopile 1, and lowering the temperature of the temperature sensing element 4. The detected temperature t ₂ 〓 rises and approaches t ₂ . In this way, when the temperature detected by the thermosensor 4 approaches and matches the temperature detected by the thermosensor 6, the difference signal 15 becomes zero, and the current controlled by the electronic cooling element control section 19 settles to a constant value, causing the sensor section L to The skin temperature of the applied body part is maintained at the true value. Therefore, the heat flow on the skin of the body part to which the sensor part L is applied has exactly the same density as the heat dissipation in the part to which the sensor part L is not applied, and the heat flow density detected by the thermopile 1 becomes the true value and is output to the recording output part. 10 and a digital display meter 11. In this way, the heat flow density of the patient's normal skin can be truly measured.

Now, as the blood flow in the arm gradually decreases as a sign that the patient's condition will deteriorate, the core temperature and skin temperature decrease and the heat flow density decreases accordingly. Such a change in heat flow density is not detected until a temperature difference appears between the front and back surfaces of the thermopile 1. When there is a change in heat flow density in the living body,
The detection signal of the thermosensor 6 becomes smaller before the detection signal of the thermosensor 4, and therefore the differential amplifier 12 outputs a positive difference signal 18, which becomes a feedback signal and is used to control the electronic cooling element. The current 17 controlled and outputted by the section 19 increases, which increases the temperature difference between the cooling side and the heating side of the cooling panel 3 made of the electronic cooling element 3a, and the temperature on the surface of the thermopile 1 decreases to the true skin temperature. As the detection signal 12 of the thermosensing element 4 becomes smaller, the difference with the detection signal 13 of the thermosensor 6 gradually becomes smaller, and when the difference disappears, the feedback signal 18 also becomes zero, and the current balances to a new value. become a state. Therefore, the heat flow density can be accurately measured even after an abnormality occurs in the patient. If the recorder determines that an abnormality has occurred, the doctor must promptly take appropriate measures to treat the patient.This treatment will prevent the patient's condition from worsening, and further measurements will confirm the above-mentioned symptoms. It is also possible to know how the patient's condition has improved due to the treatment.

In addition, in the case of patients with leucism, the heat flow density in the skin is low due to the low blood flow even during normal life compared to healthy people, and its true value is recorded on the record output unit 10 and the digital display meter 11.
No special adjustments are required depending on the patient's condition.

(4-3) Experimental example Figure 8 is a graph showing the measurement results using the biological surface heat flow density measuring device of the present invention as shown in Figure 6, where one scale on the horizontal axis corresponds to 2 minutes. The vertical axis shows the temperature and heat flow density, and the measurement location was a constant temperature and humidity room with an environmental temperature of 30°C and a relative humidity of 60%. What we can see from this graph is that
If the cooling panel 3 is not cooled, the skin temperature will be 34°C as the true value as detected by the thermistor 6, but the temperature detected by thermistor 4 will be 34°4', which is the skin temperature of the biological part where the thermopile 1 is in contact. It turns out that heat is trapped in the skin, and the heat flow density at this time is 0.19 cal/min・cm ² , and the skin temperature t ₂
When the surface temperature of thermopile 1 is brought to the same temperature by feedback control while maintaining the temperature at 34°C, the heat flow density increases to 0.26 cal/min・cm ² , which is a difference between the apparent value obtained by the conventional device and the true value obtained by this device. It can be seen that there is a considerable difference between the values. The time required for the temperature to become equal when using feedback control is 30
It was hot within seconds. Therefore, it is considered that there is no problem in practical use in terms of the ability to follow changes in heat flow density that occur as a sign of deterioration of a patient's condition.

A similar trend was observed when the environmental temperature was low (20°C).

(5) Modification FIG. 9 shows a modification of the main part of the present invention, except that no heat radiation fins are attached, and the same members as those in FIG.

The control display section N is processed so that if the temperature detected by the temperature sensing element 4 is lower than the temperature detected by the temperature sensing element 6, a negative difference signal 18 is output, and if it is higher, a positive difference signal 18 is output. Also good.

(6) Effects As explained above, the apparatus for measuring heat flow density on the surface of a living body of the present invention has a cooling panel made of an electronic cooling element superimposed on a thermopile, and the surface temperature of the thermopile can be detected with a temperature sensing element. A first sensor section consisting of a thermosensor, and a second sensor section consisting of a thermosensor that is applied to the surface of the living body, and the detection signals of both thermosensors are amplified by an amplifier, and further amplified by a differential amplifier. A control display in which the difference signal is used to feedback-control the electronic cooling element control unit that controls the current of the electronic cooling element, and the detection signal from the thermopile is amplified by an amplifier and recorded at least in the recording output unit. It consists of the following sections.

Therefore, the apparatus for measuring heat flow density on the surface of a living body of the present invention can substantially control the thermal conductivity of the thermopile as required by cooling the cooling panel even when the thermopile is applied to the surface of the living body. can be carried out as desired and smoothly to maintain the skin temperature at a temperature that does not apply to the thermopile, thus allowing a true measurement of heat flow density.

Furthermore, the device of the present invention can not only accurately measure heat flow density, but also detect changes over time when the skin temperature increases or decreases due to deterioration of the condition of the living body, and the skin heat flow density changes. It can be detected as a difference between the detection signals of two temperature sensing elements, and this difference signal is used as a feedback signal to control the electronic cooling element control unit to cool the thermopile as required by the cooling panel and apply the thermopile. The surface temperature of the thermopile can be kept in equilibrium with the true skin temperature that has newly changed due to the occurrence of an abnormality so as not to be affected by the abnormality.

For this reason, for patients who are expected to be in critical condition due to poor blood circulation, two sensor sections are applied to the patient's arms, etc., and the heat flow density in the skin is measured over time. For example, changes in heat flow density over time can indicate a lack of blood flow, which is a sign that a patient is in critical condition, and by knowing when such an abnormality occurs, a doctor can take appropriate measures. can be taken calmly, and in many cases, serious illness can be prevented, which is extremely useful in terms of clinical tests and life safety.

In addition, the heat flow density measuring device on the surface of a living body of the present invention can contribute to more accurate numerical estimation in “estimating blood flow in each part of the living body” by using it together with a deep temperature measuring device of the living body. This can contribute to a more accurate understanding of the difference in blood flow between healthy people and patients with leukemia.

[Brief explanation of the drawing]

FIG. 1 shows a conventional apparatus for measuring heat flow density on the surface of a living body, in which FIG. 1 is a simplified external view and FIG. 2 is a diagram of the principle. Figures 2 and 2 are conceptual diagrams showing changes in heat flow, respectively, and Figure 2 shows the heat flow in a state where no thermal resistor is applied to the surface of the living body.
Figure 2 shows the change in heat flow immediately after applying the thermal resistor, and Figure 2 shows the heat flow when the temperature of the living body surface rises above the temperature before applying the thermal resistor. FIG. 3 is a conceptual diagram showing the change in temperature gradient before and after applying a thermal resistor to the surface of a living body. Figure 4 is a block circuit diagram of the apparatus for measuring heat flow density on the surface of a living body according to the present invention;
Figure 6 is an exploded view and a front view of the sensor part, which is one of the main parts of the heat flow density measuring device according to the embodiment of the present invention, and Fig. 6 is a handling explanatory diagram showing the state in which the sensor part is applied to the patient's arm. , Fig. 7 is a conceptual diagram for explaining the temperature gradient in the cross section of the living body and the device during measurement with the heat flow density measuring device of the present invention, and Fig. 8 shows the experimental results measured with the heat flow density measuring device of the present invention. FIG. 9 is a graph showing a modification of the sensor section, which is one of the main parts of the present invention. L, M...Sensor section, N...Control display section, 1
...Thermopile, 3...Cooling panel, 3a...
Electronic cooling element, 4... Control thermistor, 5...
Heat dissipation fin, 6...Thermistor for skin temperature detection,
9...first amplifier, 10...recording output section, 14
...Second amplifier, 15...Third amplifier, 16
...Differential amplifier, 19...Electronic cooling element control section.

Claims (1)

[Claims] 1. Consists of two sensor sections and a control display section,
One sensor section consists of a thermopile with a cooling panel made of an electronic cooling element superimposed on it, and a control thermistor attached to the thermopile surface, and the other sensor section consists of a skin temperature detection thermistor that is separately applied to the surface of the living body. The control display section includes a first amplifier that amplifies the output signal of the thermopile, a recording output section that calculates and records the output signal of this amplifier into heat flow density, and amplifies the output signals of the two thermistors. a differential amplifier that inputs the output signals of the second and third amplifiers and outputs a difference signal; and a surface portion of the cooling panel joined to the thermopile is on the heat absorption side. and a thermoelectric cooling element control section capable of feeding a current in a predetermined direction to the thermoelectric cooling element and controlling the magnitude of the current by inputting an output signal of the differential amplifier as feedback control. Heat flow density measuring device. 2. The heat flow density measuring device on the surface of a living body according to claim 1, characterized in that the cooling panel is provided with heat radiation fins.